/* Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.activiti.engine.impl.persistence.entity;

import java.util.List;

import org.activiti.engine.ActivitiException;
import org.activiti.engine.delegate.event.impl.ActivitiEventBuilder;
import org.activiti.engine.impl.persistence.AbstractManager;
import org.activiti.engine.task.Attachment;
import org.activiti.engine.task.Task;
import org.flowable.common.engine.api.delegate.event.FlowableEngineEventType;
import org.flowable.common.engine.impl.interceptor.EngineConfigurationConstants;

/**
 * @author Tom Baeyens
 */
public class AttachmentEntityManager extends AbstractManager {

    @SuppressWarnings("unchecked")
    public List<Attachment> findAttachmentsByProcessInstanceId(String processInstanceId) {
        checkHistoryEnabled();
        return getDbSqlSession().selectList("selectAttachmentsByProcessInstanceId", processInstanceId);
    }

    @SuppressWarnings("unchecked")
    public List<Attachment> findAttachmentsByTaskId(String taskId) {
        checkHistoryEnabled();
        return getDbSqlSession().selectList("selectAttachmentsByTaskId", taskId);
    }

    @SuppressWarnings("unchecked")
    public void deleteAttachmentsByTaskId(String taskId) {
        checkHistoryEnabled();
        List<AttachmentEntity> attachments = getDbSqlSession().selectList("selectAttachmentsByTaskId", taskId);
        boolean dispatchEvents = getProcessEngineConfiguration().getEventDispatcher().isEnabled();

        String processInstanceId = null;
        String processDefinitionId = null;
        String executionId = null;

        if (dispatchEvents && attachments != null && !attachments.isEmpty()) {
            // Forced to fetch the task to get hold of the process definition for event-dispatching, if available
            Task task = getTaskManager().findTaskById(taskId);
            if (task != null) {
                processDefinitionId = task.getProcessDefinitionId();
                processInstanceId = task.getProcessInstanceId();
                executionId = task.getExecutionId();
            }
        }

        for (AttachmentEntity attachment : attachments) {
            String contentId = attachment.getContentId();
            if (contentId != null) {
                getByteArrayManager().deleteByteArrayById(contentId);
            }
            getDbSqlSession().delete(attachment);
            if (dispatchEvents) {
                getProcessEngineConfiguration().getEventDispatcher().dispatchEvent(
                        ActivitiEventBuilder.createEntityEvent(FlowableEngineEventType.ENTITY_DELETED, 
                                attachment, executionId, processInstanceId, processDefinitionId),
                        EngineConfigurationConstants.KEY_PROCESS_ENGINE_CONFIG);
            }
        }
    }

    protected void checkHistoryEnabled() {
        if (!getHistoryManager().isHistoryEnabled()) {
            throw new ActivitiException("In order to use attachments, history should be enabled");
        }
    }
}
